The present invention relates to a process for fitting a driving cab to a vehicle frame and also relates to an arrangement for suspension of a driving cab on a vehicle frame.
In most cases the manufacture of trucks or similar heavy vehicles currently involves the frame and the driving cab being preassembled separately, often in completely different workshops. Only at the stage of final assembly of the vehicle, when all the parts are fitted together, is the vehicle cab lifted into position and secured to the frame. At present this is often done by lowering the driving cab towards the vehicle frame by means of an overhead travelling crane or some other lifting device. This is followed by aligning to the correct position and securing to the frame, after which the cab can be released from the lifting device.
In so-called COE vehicles, the driving cab is placed on top of the vehicle""s engine, which is mounted separately on the vehicle frame. To make the engine readily accessible for inspection and repair, the driving cab is usually arranged to be tiltable relative to the frame. The axis about which the cab can be tilted forwards is situated in the vicinity of the front part of the driving cab. On such vehicles used for distribution and the like, a situation in which driver comfort requirements are somewhat less than in long haul work, it is usual for only the rear portion of the cab to be suspended resiliently relative to the frame. This is commonly known as two-point suspension.
At the time of assembly, the most usual practice is that the connection between cab and frame is made at or in the vicinity of the tilt axis. However, known designs often entail mobilising and fitting a multiplicity of parts in the form of fastening elements or the like. This means that a number of fitters have to co-operate. As the cab is suspended from the lifting device during the assembly process, there is a relatively high risk of personal injury due to such occurrences as pinching or crushing. For a fully sprung cab, i.e. a cab which is resiliently suspended at both front and rear edges, a solution with the aforesaid disadvantages is indicated in DE 21 61 952, which involves the cab being lowered towards the frame, followed by a locking pin having to be fitted via the lower hinged bracket of the respective spring pack. Thereafter the locking pin has to be fitted into a bearing arranged in the respective axial end portion of the stabiliser""s torque bar. Only when this pin fitting operation has been completed can the cab be released from the lifting device. Such a solution is also referred to in GB 13 99 611.
In the case of assembly according to the conveyor belt principle, the work may be done under a certain time pressure, since the cab has to be released from the lifting device before the vehicle reaches a certain point on the conveyor. Any such stress situation may further increase the risk of injury. It also entails a complicated assembly process and greater risk that any complication which arises may result in cab assembly not being completed within the available portion of the conveyor. In such situations the conveyor has to be halted until the problem is solved, thereby bringing the whole production line to a halt and delaying assembly work. The result is reduced efficiency and consequently higher production costs. It is therefore desirable for most stages of assembly to be completed before final assembly.
The problems described above may occur at the stage of bringing together the cab and frame of any vehicle which is provided with a similar forward suspension arrangement. The cab need not necessarily be of the tiltable type.
The object of the present invention is to eliminate the aforesaid problems and provide a simple solution for final assembly of vehicles with cabs with two-point suspension, whereby the working stages involved in assembling the cab to the frame are as few and easy as possible, particularly during the critical period when the cab is suspended from the lifting device.
According to the invention, this is achieved by providing the cab with a contact device with two supporting flanges which at the time of assembly are made to abut against the protruding portions of a rotatable pivot which extends through a slightly resilient support mounted on the frame. When the supporting flanges rest against the pivot, the cab lies in a relatively stable manner against the frame, and two holes in the contact device are central to an aperture extending through the supporting device. The cab may therefore be released from the lifting device and the contact device may be secured to the pivot by threading a fastening device through the apertures placed centrally to one another.
The arrangement according to the invention and further features and advantages of the associated assembly process are indicated in the ensuing description of an embodiment with reference to the attached drawings.